On Tue, Jul 05, 2011 at 09:53:19AM +0200, Arjen Smedes wrote: > Wthout brackets I get an "Unknown range operation". This means that there's no valuerangeprocessor set for the prefix "ata". I don't know much about djapian, but at the Xapian API level the setup required is described here: http://xapian.org/docs/valueranges Cheers, Olly